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Calendar of Physics Talks Vienna
| QCD in the cores of neutron stars (Vienna Theory Lunch Seminar) |
| Speaker: | Aleksi Kurkela (University of Stavanger) |
| Abstract: | Neutron stars are the densest astrophysical objects in our universe, reaching densities as high as those realized in ultrarelativistic heavy-ion collisions at the LHC. In these collisions ordinary nuclear matter melts into a new phase of elementary particle matter, quark matter. This naturally raises the question: does quark matter also exist inside neutron stars? The rapid advancement in neutron-star observations in combination with state-of-the-art QCD calculations is providing us with an unprecedented view of the extreme matter deep in the cores of the stars. In my talk, I describe how recent advancements in theory of superdense matter inform us about what lies in the centers of neutron stars and how different constraints point to the existence of quark matter cores in large neutron stars.
[[part of the "Vienna Theory Lunch Seminar, see https://lunch-seminar.univie.ac.at ]]
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| Date: | Tue, 28.11.2023 |
| Time: | 12:30 |
| Duration: | 75 min |
| Location: | TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11 |
| Contact: | Florian Lindenbauer |
| Bethe equations and 2d conformal field theory |
| Speaker: | Tomas Prochazka (Prag) |
| Abstract: | The usual approach to 2d conformal field theory relies on the underlying Virasoro algebra.
I want to discuss how this fits into a broader framework of integrable systems.
In particular, the states in the Hilbert space can be labeled by solutions of algebraic equations,
the Bethe equations. Perhaps surprisingly, Bethe equations associated to Virasoro algebra and its higher spin generalizations are very closely related to those of simplest Heisenberg SU(2) XXX spin chain. If time permits,
I will discuss the set of Bethe equations associated to 2d free boson which is closely related
to solvable generalizations of the quantum mechanical harmonic oscillator and the classical system of Calogero particles.
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| Date: | Tue, 28.11.2023 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Sem. R. DB gelb 03 (TU Wien Freihaus, Wiedner Hauptstrasse 8, 3rd floor, yellow tower) |
| Contact: | S. Fredenhagen, D. Grumiller, T. Tran, A. Fiorucci |
| Ion implanted quantum structures in solid state matrices |
| Speaker: | E. Harriet Ã
hlgren (Accelerator Laboratory, Department of Physics, University of Helsinki/Finland & Department of Physics, University of Vienna) |
| Abstract: | Impurity atoms in solid state materials offer a flourishing platform with properties well suited for various
applications from catalysis to quantum information technology. In this talk I will introduce our recent work on designing new atomic scale structures within solid state frames by ion implantation and subsequent characterisation by high-resolution scanning transmission electron microscopy and spectroscopy. Firstly, I will discuss two dimensional materials as a functional frame for impurity atoms, focusing on structures both within the 2D layer and between the interface of two sheets, covering their stability and challenges working with such systems. The structures are created by ultra-low energy ion implantation at the eV energy range, which serves as a versatile method to achieve various nanoscale structures. Secondly, I will introduce optically active impurity centers created in |
| Date: | Tue, 28.11.2023 |
| Time: | 16:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner HauptstraÃe 8-10 Yellow Tower âBâ, 5th floor, SEM.R. DB gelb 05 B |
| Contact: | Assoc.Prof. Dr. Richard Wilhelm |
| Compactness of minimizing sequences for the Einstein-Vlasov system |
| Speaker: | Hakan Andreasson (Goteborg) |
| Abstract: | It is well-known that spherically symmetric steady states of the Vlasov-Poisson system can be obtained as minimizers of an energy-Casimir functional.
This has played an important role for the celebrated stability results in that case. It is also well-known, cf. the recent review paper by Rein arXiv:2305.02098,
that there are no analogue results for the Einstein-Vlasov system, mainly due to lack of compactness.
In this talk I will close this gap by showing compactness of minimizing sequences to a particle-number-Casimir functional, which then implies the existence of a minimizer.
Under a regularity assumption it follows that the minimizer is a steady state of the spherically symmetric Einstein-Vlasov system.
As a consequence of the proof, a condition arises which we believe is sufficient for non-linear stability. This is a joint work with Markus Kunze. |
| Date: | Wed, 29.11.2023 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer StraÃe 17, 2. Stock |
| Contact: | P. Chrusciel, D. Fajman |
| On sub-shot-noise scaling in parameter estimation in critical many-body systems |
| Speaker: | Mohammad Mehboudi (TU Wien, Atominstitut) |
| Abstract: | Many-body systems are very good sensors when tuned close to their critical points. In particular, these systems may undergo a phase transition by a tiny change of the order parameter, making it extremely sensitive to the parameter. Their usefulness in metrology has been quantified by showing that their Fisher information scales super-linearly in the vicinity of the critical point. The Fisher information is, however, a relevant figure of merit in local parameter estimation, i.e., when the parameter is readily known with a good precision. More realistically, one has a limited knowledge about the parameter, often given by a prior distribution. Such scenarios are often dealt with a Bayesian approach to parameter estimation.
Here, we would like to investigate critical quantum metrology, through the lens of Bayesian inference theory. We first derive a no-go result stating that any nonadaptive |
| Date: | Wed, 29.11.2023 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Maximilian Prüfer |
| Fracton gauge fields from higher-dimensional gravity |
| Speaker: | Patricio Salgado-Rebolledo (TU Wien) |
| Abstract: | Fractons are novel quasiparticle excitations with restricted mobility that have attracted increasing interest in recent years by both condensed matter and high energy physicists. In certain fractonic systems, mobility constraints are associated with the conservation of the dipole and/or higher moment charges, leading to the so-called multipole algebra. In this seminar we will show that the dipole-conserving algebra can be obtained as an Aristotelian/pseudo-Carrollian contraction of the Poincaré algebra in one dimension higher. When applied to a higher-dimensional curvature-squared gravity theory, the contraction produces several models for fracton gauge fields, including the fractonic generalization of Maxwell electrodynamics originally proposed by M. Pretko. A curved space generalization is given, which is gauge invariant when the Riemann tensor of the background geometry is harmonic. |
| Date: | Thu, 30.11.2023 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room 10th floor |
| Contact: | Iva Lovrekovic |
| Engineering vortex matter in strongly-correlated superfluids |
| Speaker: | Giacomo Roati (LENS Florence) |
| Abstract: | Topological defects determine properties and structure of disparate out-of-equilibrium physical and biological matter over a wide range of scales, from planetary atmospheres, turbulent flow in hydrodynamic classical and quantum fluids, up to electrical signalling in excitable biological media [1]. In superfluids and superconductors, the motion of quantised vortices is associated with the onset of dissipation, limiting the superflow [2]. Understanding vortex dynamics is a formidable challenge because of the complex interplay between moving vortices, disorder and system dimensionality that encumbers predictability.
We approach this challenge by realizing a novel programmable vortex platform in planar homogeneous Fermi superfluids [3]. We engineer vortex configurations on-demand and we monitor the evolution by directly tracking vortex trajectories. The ultimate control on the vortex dynamic |
| Date: | Fri, 01.12.2023 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Maximilian Prüfer |
| Hide and seek: how PDFs can conceal new physics |
| Speaker: | Maeve Madigan (Univ. Cambridge) |
| Abstract: | The Standard Model Effective Field Theory(SMEFT)provides a powerful theoretical framework for interpreting subtle deviations from the Standard Model and searching for heavy new physics at the LHC.
Accurate interpretations of LHC data,however,rely on the precise knowledge of the proton structure in terms of parton distribution functions(PDFs).In this seminar I will discuss the interplay between PDFs and the search for new physics.I will showcase a scenario for the High-Luminosity LHC in which the PDFs may completely absorb such signs of new physics,thus biasing theoretical predictions and interpretations.
To address this challenge,I will present a simultaneous determination of PDFs and the SMEFT using the SIMUnet methodology.This approach integrates both PDF and SMEFT determinations into a single,coherent framework,making possible an assessment of of the regions of parameter space ... |
| Date: | Fri, 01.12.2023 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Josef-Stefan-HS, Boltzmanngasse 5, 3. Stock |
| Contact: | A. Hoang, M. Procura, T. Corbett |
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